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# Physics Average Speed Question watch

1. A vehicle joins a motorway and travels at a steady speed of 25ms-1 for 30 min then it travels a futher distance of 40km in 20 min before leaving the motorway.

Calculate the average speed on the motorway

Equation to use: s/t

I worked out the distance travelled for the first 30 mins which is 450,000m. I really need help on this question, I've been stuck on it for 20 mins Thanks to anyone who helps!
2. (Original post by Whatever210)
A vehicle joins a motorway and travels at a steady speed of 25ms-1 for 30 min then it travels a futher distance of 40km in 20 min before leaving the motorway.

Calculate the average speed on the motorway

Equation to use: s/t

I worked out the distance travelled for the first 30 mins which is 450,000m. I really need help on this question, I've been stuck on it for 20 mins Thanks to anyone who helps!
average speed = total distance/ total time

Also
25 * 30 * 60 = 45 000
3. You're a factor of 10 out on the first distance as I make it - think it should be 45,000m (typo?)
(comes from 30 mins x 60 secs x 25 ms-1)

Then for average speed need to divide total distance (45,000 + 40,000 = 95,000) by total time (30 mins + 20 mins = 50 mins = 3000 secs) giving 31.67 ms-1 or 114 km/h
4. to 2nd poster ^ I typed it out wrong but that is the answer I got.
I know the formula, I'm asking how you get the answer because I can't. Thanks for your input though

5. (Original post by Whatever210)
to 2nd poster ^ I typed it out wrong but that is the answer I got.
I know the formula, I'm asking how you get the answer because I can't. Thanks for your input though

Post ur working n we will have a look.
6. spread_logic_not_hate gave the right answer except there's a mistake in your total distance calculation which may be a typo, anyway thanks.
7. (Original post by Whatever210)
A vehicle joins a motorway and travels at a steady speed of 25ms-1 for 30 min then it travels a futher distance of 40km in 20 min before leaving the motorway.

Calculate the average speed on the motorway

Equation to use: s/t

I worked out the distance travelled for the first 30 mins which is 450,000m. I really need help on this question, I've been stuck on it for 20 mins Thanks to anyone who helps!
do it in two parts:
1)d=s*t
d=25*(30*60)
d=25* 1800
d=45000

40km = 40 000m

so 45 000m + 40 000m = 85 000m or 85km

2) 20min +30min = 50min = 50*60sec = 3000sec

so

85 000 = 28.33ms-1
3000
8. (Original post by Boristhethird)
do it in two parts:
1)d=s*t
d=25*(30*60)
d=25* 1800
d=45000

40km = 40 000m

so 45 000m + 40 000m = 85 000m or 85km

2) 20min +30min = 50min = 50*60sec = 3000sec

so

85 000 = 28.33ms-1
3000
I think It should be 3000/85000 and not it's reciprocal
9. (Original post by RVNmax)
I think It should be 3000/85000 and not it's reciprocal
speed = distance/time
speed = 85000/3000
10. (Original post by Boristhethird)
speed = distance/time
speed = 85000/3000

yep my mistake, sorry about that lol
11. (Original post by RVNmax)
yep my mistake, sorry about that lol
no offence but i actually feel cleaver! i got something correct!

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